Alphons



1 UNITED STATES j PATENT ferries unions 0. JAEGER, or neuiv'r LEBANON, PENNSYLVANIA, Assmiv'oa 'ro THE sELnim' couramr, or rrr'rsnnaen, PENNSYLVANIA, A conrona'rron or DELAWARE,

con'mcr sunrnunrc non) PROCESS Io Drawing. Original No. 1,675,808, dated June 26, 1928, Serial 1%.. 210,462, filed August 3, 1927.

' Application for reissue filed April 5, 1930. Serial No. 442,031.

This invention relates to the catalytic oxidation of sulphur dioxide to sulphur trioxide, the socalled contact sulphuric acid process. V

According to the present invention, gaseous mixtures of sulphur dioxide and oxygen are oxidized catalyticallyr at the usual elevated reaction temperatures in the presence of catalysts which when freshly prepared, contain catalytically active diluted or undiluted IlOIl-SlllClOl-lsbflSG exchangebodies or their derivatives, some of which new catalysts have been described and claimed as products in my application, Serial No.

171,727, which matured into Patent No. 1,694,620 dated December 11, 1928, filed F ebruary 28, 1927, of which the present appli cation isin part a continuation.

Such non-silicious base exchange bodies can be produced b the reaction of alkaline so lutions of amp oteric metal hydroxides .with

non-alkaline solutions of other metal com-V troduced should preferably be catalyticallyactive 'in'the oxidation of sulphur dioxideto sulphur trioxide. Catalyst-s can be produced by bringing about the reaction between a single metallate and a single metalsalt, one or both being catalytically active, or a plurality of metallates or a plurality of difl'erent metal salts can be used. In some cases the same metal maybe present both as metallate and as a metal salt. In the case of some amphoteric metals, metallates and metal salts can be used in which the metal has the same valence. In the case of other metals, metallates are formed in one state of oxidation and metal salts in a 'difl'erent state of oxidation, usually a lower one.

All of the base exchange bodies used in the present invention, that is to say, catalytically active bodies which are prepared by the reaction of a single metallate with a single metal salt or bodies produced by the reaction of at least one metallate. with a plurality of metal salts, 'or vice versa possess bodies and their derivatives.

a remarkably porous, frequently microporous structure and in somecases are opales- When suitable catalytically active" cent. components are present in the products,v they form catalysts of remarkable efliciency due probably to the extraordinarily high surface energy of the microscopically porous structures and probably also to 'the presence of .sible that molecular mixtures are present.

The products possess a physically microscopical homogeneity and behave in many ways as if they were single compounds, and I am of the opinion that'probably in many cases the products are in fact single compounds of very high molecular weight but the invention is not limited to any theories of the chemical constitution of the products.

It should be clearly understood that the products used in the present invention are .chemically quite distinct from base exchanging bodies containing silicon, suchas for example the zeolites and related base exchange The present compounds contain no'silicon in theirstructure, and while they share many of the physical properties of zeolites, namely, the highly porous structure and the power of exchanging their alkali cations for other cations by base exchange, they are chemically dis tinct products. Surprising, as it may seem. the presence of silicon, which has hitherto been considered as essential .to the formation of skeletons of such advantageous physical structure, appears to be only one of many elements which arecapable of forming products having these physical properties, and many of the base exchange bodies used in the present invention'possess the mechaniv the like.

and it is therefore possible to de siderably cal strength and resistance of the silicious zeolites, propertia which are of course of utmost importance inthe contact sulphuric acid"proces s'.

A number of elements are capable of formin alkali metal metallates, at least in their higher states'of oxidation, andcan be used singly or in mixtures, as the-metallate components for producing, baseexchange bodies used in the present invention, it being understood of course that the choice will depend" on the metal salts to be used and on the catalytic effects which it is desired to produce. Among the elements which form metallates are the following :aluminum,

chromium, zinc, vanadium, beryllium,rtin, palladium, platinum, titanium, zirconium, tungsten, lead, uranium, tantalum, boron, molybdenum, The elements which form the metallates may be present in the form of their oxides or hydroxides united with alkali to form simple metallates, or they may be present partly or wholly in the form of complex compounds, such as for example, ammonia complexes, cyanogen complexes, and

In general, "the complex comounds described in the application 'of aeger and Bertsch, Serial No. 100,116,'filed April '19, 1926, which-matured into Patent 0? 1,782,353 dated Nov..,18, 1930, maybe use The metal salt components include the water soluble neutral or acid salts of the following elements ::copper, silver, gold, beryllium, zinc, cadmium, aluminum, rare earths, titanium, zirconium, tin, lead, thorium, chromium, uranium, vanadium, man ganese,.1ron, n ckel, cobalt, platinum, palladium, which may be used singly or in any It is an advantage of desired mixture. the present invention that definite proportions of the individual compounds do not need to be used, either because mixtures of difierent compounds are formed, or more probably because the tremendous size and complexity of the molecule masks any requirements for definite proportions.

All of the products used in' the present invention possess base exchanging powers to a greater or 1cm extent when first prepared in solutions which are substantially neutral or alkaline to phenolphthalein. For the contact sulphuric acid-process, however, the base exchanging 'power of the products is not required in the catalytic reaction itself rt confrom the optimum con itions of production as far as base exchan e ower oes. In otherwordea'the'limits 0 al alin- .lty, neutralityor"."aicidityl are much wider than softening, andwhic therefore depend rimarily on their base 'exchangin power.

ile usually the highest base exc anging' powers are obtained when-the compounds are produced in a, reaction mixture which prepared with somewhat difierent propor-v tions of the components, so that at the end of the reaction the mixture may possess any alkalinity or acidity between. phenolphthalein red and litmus blue as indicator end points.

The possibilities of producing catalysts 1 according to the present invention are not limited tothe reaction products of the metallates and metal salt components which may be used and which are present in the molecules in anon-exchangeable form. -()n the contrary,-a further series of produc s can be prepared by exchanging part or all of the alkali cations for other atoms or radicals by means of base exchange. The number of cations which can be introduced is very large, and some of them are included in the following elements and radicals ammonium, copper, silver, gold, beryllium,

magnesium, caesium, zinc, strontium, cadmium barium aluminum thallium tita- 7 7 i nium, zirconium, tin, thorium, vanadium,

chromium, uranium, manganese, iron, cobalt, nickel, palladium, platinum. These cations may be introduced either singly or in mixtures, simultaneously orsuccessively. The widev possibilities of combination which can be effected by the introduction of various cations by means of base exchange gives the catalytic'chemist an almost'infinite field of ice choice in preparing catalysts having'just the 7 right degree of activity for the contact su phuric acid process audits is an advantage of the present invention that "catalysts of exceedingly finelyadjusted activity can be produced and are efiective. The cations in troduced by base. exchange maybe themselves catalytically active, or they may activate catalytic components which are pres tained is enhanced by the'favorable physical structure of the base exchange body.

A further series of products can be obtained by treating the base exchange bodies used in the present invention either with ore of reaetingwith the base exchange body to formsalt-like products.

ent invention, the catalytically efi'ective components may be present solely in the base exchange body, solely in the union of the "salt-like body or partly in one and artly in 130 the other. Acid radicals ofthe ollowing In the contact masse containing 1 salt-like bodies, which are used in the pres- 11L ent in the products in non-exchangeable form. Cations may; also be introduced as simple ions or as complex ions. In all cases,

the catalytic activity of the products ob-' elements, either simple acids, polyacids or complex anions, can be used in producin salt-like bodies with the base exchange 'bo ies of the present invention :vanadium,

tungsten, uranium, chromium, molybdenum,

maganese, tantalum, titanium, bismuth, sul- 0 and the like,

- phur, chlorine, platinum, boron. Coinplex ions, such as for example, ferro and farmcyanogen, sulphocyanogen, meta-l cyanogen,

form salt-likebodies with'the base exchanging bodies of-the present invention. A $111,-

gle acid radical may be introduced, or a mixture may be had, either by a simultaneous or successive treatment. The amount of the acid radical usedmay also be varied so that the products may possess the character of acid, neutral or basic salts.

While the number of catalytically active or'activating elements which can be introduced is very large, I have found that the ,most effective and satisfactory catalysts are those which contain vanadium, with or with- I out other catalytically active elements. The

- ,be coated on or impregnated in relatively diluted. form, best results homogeneous structure. finely divided carriers, diluted or, undiluted tion of present invention is not limited in its broader aspects to the use of non-slllcious base exchange contact masses in which vanadium is present, but in its more specific embodi-' ments such vanadium-containing contact masses are included, and constitute the preferred contact masses for the present invention. While it is possible to use certain of the catalysts of the present invention in an un are usually obtained by the dilution of the products with more or less inert bodies,'or with bodies of relatively feeble catalytic powersor activating powers. Diluents can be incorporated with the catalytically active base exchange body. before or after formation, and are preferably although not necessarily, incorporated therewith to produce a physically In addition to catalytically active baseexchange bodies can massive carrier fragments, the incorporation taking'place before, during or after formathe base exchange body. It should be understood of course in all cases that course impossible to incorporate luents or carrier bodies,

may also be used wherever they used in the present diluents from the broader aspects of the present invention. 7

A large number of diluent bodies can be' used, such as silicious materials, as kiese lguhrsof all kinds diatomite brick refuse pumice meal, pulverized quartz, sand, an other minerals, especiallythose rich in sillca.

In the same way, a large number of natural or artificial massive carrier fragments can be used, such as fragments of pumice, diatomite bricks or other minerals, metal granules and the like. In general, the methods of incorporation and many of the diluents which can be used are described in the copending application of Jaeger and Bertsch, Serial No. 95,771, filed.March"l8,

lfhe high porosity of the products which are prepared may be even-further increased I by incorporating into the framework of the base exchange body products which can be removed'by leaching, volatilization or com-' bustion, and which when removed leave additional porous spaces and produce an even more advantageous ph sical structure. 1 The substances added may be of organic or inorganic nature and'may be added as individuals or may be in chemical combination with some of the permanent components; Thus for example, certain of the components may be introduced in the form of complex compounds which'are'later decomposed and then leave additional porous spaces. Ex-

amples of such complex compounds are oer tain ammonia complexes which can be decomposed by heating the finished product.

In general the reaction of the componentsolutions results in the production ofsoluble salts which are not wanted, and it is therefore usually desirable to wash the base exchange body, after preci itation and then to dry, or dry first and tlien wash. I have found that while it is possible in some cases to dry at high temperature, for the best results,

in most'cases drying temperatures of (3., or less, are desirable In the general methods described above,

separately prepared metallate components and metal salt components have been caused to react. While for many purposes these are the preferred methods, it is-possible to prepare base exchange bodies by somewhatdiiferent methods. Thus for example, if a solution of a metallate or amphoteric metals is'cautiously neutralized with acid until the strongly alkaline reaction becomes weakly acid with weak alkalinity to litmus,- as a limit, base exchange bodies are produced, and in many cases are of importance, particularly' for the contact sulphuric acid process. Instead of the metallates, the amphoteric metals may also be. present in the form of complex metallate compounds, for example, i v such complex compounds as are described in alkaline to phenolphthalein, or even slightly the co-pending application of J aeger and Bertsch, referred to above.

' In a simllar manner, acid or neutral solutions of salts of amphoteric metals maybe treated with alkali'untiluthe mixture be-' comes neutral or alkaline to phenolphthalem, or even acid, in which case base. exchange bOdlGS are produced in a manner.

v similar to that dsecribed in the foregoing paragraph. The base exchange bodies producedeither by neutralizing metalla-te solu tions or metal salt solutions in general do not show quite as great base exchange power as do those which are prepared by causing ready made metallate and metal salt solutions o react with each other. The physical structure however, appears to be similar and, as

in many cases, particularly the contact sul.

phuric acid process, extremely hi h base exchange power is notessential, any very valuable catalysts can be produced in this manner.

A further wet preparation consists in. cansing alkali metal salts of the oxy n-containing acids of metal elements of t e fifth and sixth group of the periodic system, such as for example, vanadium, molybdenum, tant-alum, tungsten, and the like, to react withneutral or acid salts of metals, particularly metals which are strongly amphoteric. Preferably there should be an excess of alkali. The salts of the fifth and sixth group metalacids may be used alone or in combination with other metallates. 4

' In addition to the wet methods,which for most purposes I find are preferable, base exchangebodies can be produced by fusion methods, for example, by fusing oxides or hydroxides of the metallate and metal salt components with alkali, for example, sodium carbonate or potassium carbonate or \other hydroxides. The base exchange bodies produced by fusion, while sometimes they do not possess quite as high' base exchange powers, are nevertheless of asimilar advanftageous physical structure, and many-of the products are very valuable/catalysts. Ox-

ides of the metals of the fifth and sixth Solutions of alkali andalkaline earth metal.

group may also be used to form products somewhat similar to those described in the preceding paragraph by fusion methods."

Many ofthe base exchange bodies used in the present invention possess sufiicient mechanical strength, but in some cases, for y example in certain casesv of high dilution, the mechanical'resista'nce may be insufiicient,

and in such cases the products may be-washed with a dilute solution of waterglass, produc-- ing a surface silicification which adds greatly to the mechanical strength of the product.

compounds are also desirable. I

I have found it is usually desirable although not in all cases essential, to calcine be contact masses used in the present invention, and to subject them to a preliminary treatment with acid gases, such as for example S0 and air, before they are used for the catalytic I oxidation of sulphur dioxide. While this constitutes the preferred embodiment of the resent invention, the latter is not liinited thereto, and in some cases it is possible or even desirable to omit the pre- I liminary treatment, such processes being of course includedwithin the scope of the present'invention." r V The range of catalytically active elements which can be incorporated into non-silicious base exchange bodies used in the present invention is of course very wide, and includes not only vanadium in difi'erent stages of oxi- ,dation and allied catalytic elements, but also platinum and the platinum metals. In its broader aspects therefore the invention is not limited to a non-platinum catalyst, as the advantages of high porosity, strength, atomic dispersion'of call active atoms throughout the framework of the large base exchange .molecule enhance the activity of platinum and platinum metals mechanical the catalytias they do othercatalytic elements. The 1 non-platinum contact masses of the present invention, and particularly those containing vanadium, possess the important advantage .0 'overithe platinum catalysts now in use'that they are substantially insensitive 'to the]- poisons which will rapidly ruin the' ordinary platinum catalysts, metalloids, as for example, arsenic and chlorine, acid compounds, .such as hydrochloric acid, and the like, and similar poisons. It is therefore an important advantage of the preferredeinbodimentsof the present invenw tion, that it is possibleto carry out the contact sulphuric acid rocess, even when using raw materials whic are relativelyhigh in components which yield catalyst poisons for it being only necessary to remove mechanically entrained dust, which mi ht tend to clog the catalyst. Since the ela crate purification installations where platinum catalysts are used constitute quite a notable investment, the feature of their elimination which is possible with the preferred catalysts of the present invention, is of very greateconomic importance. i I

The great resistance to high temperatures ofthe catalysts used in the present invention,

base exchange bodies, is another very practical advantage of the process of the present invention, as it renders an accurate temperature control less necessary, and-the bad resuch as volatile platinum, without any'chemical purification, i

and particularly the vanadium-containing sults from occasional heating are minimized.

It is thus possible to operate the process with less care and less supervision than where more delicate -.catalysts are used, which correspondingly simplifies and cheapens: the

process according to the present invention over those hitherto used.

A further advantageof the present inven: tion over most. of the catalysts used inthe past, such. as for example platinizedasbestos, one of the best known and most effective of the catalysts used in the'past, lies in the fact that it is possible to produce the contact 10 masses used in the present invention in the form of granules, which can bereadily filled "into converters, and which do not tend to mat down and thus increase the resistance to the passage of gases therethrough. This renders the periodic removal and regeneration of the catalyst necessary at less frequent intervals, and when so removedit is usually only'necessary to sift the catalyst to remove the small proportion which may be crumbledi'n years of use. Contact masses 7 such as platinized asbestos, however, cannot platinum and to makenew contact. masses, a

- broadly, processes in which non siliciousbase exchange bodies are used 1n comblnation with be so treated, and it is necessary to recover the procedure which entails of active material.-

The diluents referred to above are for the quite a serious loss most part catalytically ineffective, but the in vention is not limited to processes in which the effective catalytic components reside solely in the non-silici-ousbase exchangebody, and in some cases it is desirable to incorporate catalytically' effective components into the diluents, which ma) be eflected in any suitable manner, as described fully in my prior Patent No. 1,694,123 dated December- 4, 1928, in which I have described and claimed processes for the catalytic oxidation of sulphur dioxide in the presence of catalysts containing .catalytically inefi'ective. base exchange bodies united with catalytically effective diluents. I do not claim here catalytic-ally effective diluents.

The base exchange bodies used in the present invention for the most part contain exchangeable bases which are not catalytically active, and which act as stabilizers, moderating and tuning the action of the catfalytic components. Among such stabilizers are the alkali metals, the alkaline earth metals, many ofthe earth metals, and similar-strongchemical bases which may be present in the form of their salts orother' compounds. Many of the amphoteric metal components of the base exchange bodies which are not catalysts of sufiicient activity to' .be commercially usable but which possess some catalytic powers, appear to enhance and tune the stabilizing action of-the strong bases present, and I have termed such inefiective catalytic components stabilizer promoters.

The diluents may also be rich in stabilizer promoters, such as for example oxides or compounds of some of the heavy metals, and the like. Ezmmple 1 40 parts of V 0, are suspended in 500 parts of water and acidified with a little concentrated sulphuric acid. The suspension is heated almost to boiling and gases containin S0 are passed through until the vanadic acid suspension is completely dissolved as' blue vanadylsulphate. Sometimes it is necessary to add some water in order to get the vanadyl sulphate entirely dissolved. The blue solution is then divided into two parts, one of which is kept as such, and. the other treated with 5 N. potassium hydroxide solution at 50'to C. until a clear cofi'ee brown solution of potassium'vanadite is obtained.

The vanadite solutionis mixed with parts of small diatomite brick fragments or 40 parts of Celite and 40 parts of quartz articles, the mixture being stirred until it ecomes uniform. Other-diluent bodies such as neutral silicates, sand, silica gel, [ground rocks, tufl's, lava of volcanic or eruptive origin, or similar materials may be used. To the solution -containing potassium vanadite the second halfof the vanadyl sulphate so.- lution is added, care being taken that even after all of-the vanadyl sulphatehas been' added, the solution remains alkaline or neutral to p'henolphthalein, The reaction product, after separation from the mother liquor by filtration is dried at 60to 70 C.. and broken into fragmentsand constitutes a base exchange body containing potassium and tetrayalent vanadium, part of :the vanadium playingthe part of an acid radical and part of a base in the non-exchangeable nortlon of; the molecule.

The product obtained after c alcination with'air and S0 gases .diluted with air at 400 to 500 C., is well suited for the catalytic oxidation of sulphur dioxide to sulphur tripassed over the contact mass at 420 to 500 C. 0 Example 2 v A diluted vanadyl base exchange body is' prepared as described in Example 1, and

is afterwards sprayed with 35% inorganic acids, such as, for example, sulphuric acid, hydrochloric acid, or the like until the alkali in the exchangeable part of the base exchange body has been neutralized and a 50-. I further called salt-like body is obtained;

The product so obtained without treatment is well suited forthe catalytic OXl? dation of sulphur dioxide to sulphur'trioxide using 6 to 8%- burner gases passed over. the

contact mass at a temperature of 420 to 550 C. A high percentage conversion to S0,

is obtained.

110 oxide, '6 to 8 per cent burner gases being Example 3 A dilutedvanadyl base exchange body, as described in Example 1, or its salt-like body, as described in Example .2, is coated. onto massive carrier fragmentsof natural or artificial origin, such as, for example, materials rich in silica as quartz fragments, quartz filter stones, sand stones, fragments of silica gel, diatomaceous stones, Celite bricks, pumice fragments, fragments of natural or artificial'silicates and diluted or undiluted zeolites, metals such as aluminum granules, metal alloys, such as ferrosilicon, ferrovana dium, ferrochrome, and the like, particularly y when their surface has been roughened' The coating can takeplace either after I formation of the product, or the product can be ea-used to react on the carrier fragments and be generated in situ.

Artificial carrier fragments can also be prepared, for example, by forming fragments of Celite, kieselguhr, pulverized quartz, silica gel, pulverizeclsilicates and diluted or undiluted zeolites, using various ad- 'hesives such as .waterglass, alkalies and alkali metal salts followed by calcination at 4:00 to 500 C. and if desired treatment with inorganic acids such as sulphuric acid, nitric I acid, hydrochloricacid and the like.

In coa'ting such carrier fragments an undiluted vanadyl base exchangefbody can be i applied, especiallyiwhen generated in sit'u.

For the preparation of such an undiluted vanadyl base exchange body it is only necessary to omit the diluent bodies, as described in the foregoing examples. In order to get a good coating on the carrier frag ments, if necessary, various adhesives can be used, such as, for example, alkalme and neutral salts of the alkali-forming metals,

such as, sulphates, chlorides, nitrates, waterglass, carbonates, hydroxides and the like.

The ratio of coating-is about 1 kg. by weight of diluted or undiluted vanadyl base exchange body per liters of pea sized carrier fragments.

Instead of introducing diluentbodies into the base exchange body during formation, as

described in the foregoing examples, the undiluted base exchange bodycan be prepared from its. components, potassium vanadite and vanadyl sulphate and mixed mechanically in aqueous suspensions with diluent bodies, or-the base exchange body may be dried and then pulverized and then mixed with the latter. For example, parts of Qelit'e brick particles may be used and the.

mixture formed into granules with anyof the .above described adhesives. Theproduet thusproduced is. an eflicient catalyst for the catalytic oxidation of S0 to S0 when 6'8% burner gasesat the usual gas velocities'aremean 7 passed over these contact masses at a tempers atllre range of 430to 550 C;

I Eammp le 4 20 parts of V 0 in 500 parts of water acidified with a small amount of concentrated sulphuric acid are reduced to vanadyl sulphate by reducing agents such as, gases containingISO 1 The blue solution obtained is treated with sufiicient 2 N. potassium hydroxide solution to precipitate a volumi nous brown precipitate of V 0 which. is then' sucked and suspended in 200 parts of water. This suspension is gradually warmed to 70 and suflicient 2 N. potassium hydroxide solution is added until the 'so I V50, dissolves to a coffee brown solution.

This requires an excess of potassium hydroxide. 1

The potassium vanadite thus produced is then stirred with 60 to parts of diatomite brick refuse or other materials richin silica, such as, diluted or undiluted base exchanging aluminum polysilicates or ground glaucosil which is the silicious residue-from the acid extraction of green sand, and 2 N.

sulphuric acid is gradually poured into the suspension with vigorous agitation until the latter just. remains alkaline to phenolphthalein.

The sulphuric acid brings-down a brown precipitate which is pressedand then dried at temperaturesbelow C. p 1

The product thus obtained which is a vanadyl base exchange body is saturated with dilute waterglass solution formed of 100 parts of 33 B. waterglass solution diluted with 100 to 150 parts of water.

After impregnation the product is again dried and broken into fragments and treated at450 to 500 C. with 7% burner gases. In a short time an excellent contact sulphuric acid process sets in. Instead of using this S0 gas concentration lower percentages and higher percentages of S0 gas can be used with great success giving good conversions to S0 This contact mass shows a good resistance to' the high temperatures often obtained in the contact sulphuric acid process.

Emample 5" 20 parts of V 0 are reduced to a vanadyl sulphate solution as described in the foregoing example and are diluted with about 70 parts of unground infusorial earth. 2 N.

potassium hydroxide solution is added in 4 portions with vigorous agitation until the mixture just remainsalkaline or neutral to phenolphthalein.

The body precipitated is treated in the usual manner as described in the foregoing examples and. is also a contact mass of excellent catalytic efliciency for the contact sulphuric acid process,- using 6-870 burner gases at a temperature of 550 to 430 in the gas flow through the converter, whereby a high percentage conversion of S to S0 is obtained.

Emumple' The diluted base exchange bodies, as described in the foregoing examples in which the diluents are incorporated into the-base exchange body during its formation, are prepared with diluents which have been impregnated uniformly with -to 10% iron silicate, silver silicate, copper silicate or their mixtures, and the like, produced by reaction of the corresponding nitrates with diluted water glass solutions. This impreg nation is carried out as follows: The diluents such, as diatomite' brick refuse or comminuted glaucosil, are suspended in sufiicient Water and the proper amount of diluted v waterglass solution, about 10%,- is added to the suspension and then a corresponding amount of 10% of the nitrate solution is added to precipitate out the silicate in a very fine distribution. v

These diluted base exchange bodies,'when broken in small pieces, are calcined with air at'about 400 and afterwards pretreated with 3. to 4% S0 gases at "400 to 500 0.

The silicates embedded with the diluents in. these base exchange bodies act as-sta-l I bilizer promoters in the contact sulphuric acid process and such contact masses are very resistant to high temperatures;

I Emample '2 12 parts of vanadic acid are treated with sufficient 2 N. potassium hydroxide solution so that not only is all of the-V 0 dissolved .in the form of potassium vanadate but an excess of 14 parts of 100% KOH remains.

A mixture of 120 parts of comminuted lnated with the above described solution. The second base exchange body compo nentnecessary is prepared by reducing. 10

quartz and 20 partsof kieselguhr is impregparts of vanadic acid to vanadyl sulphate in the usual manner and neutralizing the excess sulphuric acid with 2 N. potassium hydroxide solution.

Solution 2 and suspension 1 are. then kneaded together thoroughly and dried at temperatures below 100 C.

The productthus obtained is a base exchanging bodyv containing V 0 and V 0 The'large lumps of this product are then mbroken i nto small fragments of suitable size to be filled in contact sulphuric acid converters and after preliminary-treatment with 3 'siderable period of time parts of aluminum oxide, 20 parts of alumicellent contact sulphuric acid process setsin. "I EmampZe 8 18 parts of vanadium pent oxide-are suspended in 300 parts of water rendered weak- I 1y acid with concentrated sulphuric acid and reduced with well known reducing means sulphur dioxide, .to' blue vanadyl sulphate in the usual manner-A such as, for example,

The solution is boiled l50parts of water.

10 parts of aluminum oxide are transferred and concentrated to into potassium aluminate by-means of 5 N.

sodium hydroxide solution. of the'vanadylsulphate solution,described above, is treated with ION. potassium hydroxide'solution to transform it into coffeebrown potassium vanadite which a is then mixed with the sodium aluminate. solution to 6% burner gases 450 to 500 C an ex- L and 100 parts of infusorial earth or natural or artificial base exchanging aluminum polysilicates added To'this solution is added the potassium aluminate solution and then the remaining% of the vanadyl sulphate solu-' tion are added with being taken that remains stronglyalkaline to litmus. c

The product is pressed, dried as usual under'100 (1., broken into fragments. and if necessary sprayed with about 10%sulph'uric acid until the so-called salt-like body is formedwith the potassium vanadyl .alumi I is diluted with infusorial earth. During the spraying the fragments should preferably be heated andstirred.-'

p j This contact'mass has a high catalytic efiiciency for the contact sulphuric acid process givingiexcellent conversions at regular and somewhat higher loadings-with? to 9% burner gases.

num base exchange body which Example 9 I I A diluted base exchange bodydspre'pared as described in Example 8, but instead of ca-us'ing it to react with sulphuric acid to forma salt-like body it is with a 5% copper sulphate solution whereby part 'ofithe alkali is substituted by copper.

The product thus-obtained is a good contact mass for the contact sulphuric acid process and showsa good resistance againstjhigh temperatures. Instead of a-Copper sulphate'solution, other salt solutions, such as acalcium chlorideso lution, titanium sulphate solution, aluminum sulphate-solution and the like can be used singly or in admixture.

I Ea2( z mple 10 I A base exchange body is'pre ared as described in Example 8 but instea of using 10 vigoro'us agitatiomcare the final reaction product digested for a con- .num oxide and a corresponding amount of potassium hydroxide is used the potassium aluminat'e solutionbeing diluted with 60 to y "-70 parts of kieselguhnpumice fragments or quartz fragments, the alkali base exchange body being neutralizedwith sulphuric acid to form a salt-like body.

The alumi nate solution can be wholly or 'partl, substituted by potassium cadmiate. Thls contact mass is also well suited for the contact sulphuric acid process using regular speeds of burner gases at temperatures between 430 550 p p v I "EwampZe1 1 f I Q A vanadyl base exchange body'is prepare -by suspendin 20 parts of V in .500 parts of water, ad ing a little concentrated sulphuric'acid vand'then reducing the V 0, with .gases containing sulphurdioxide at the, boilingpoint of the solution until it is completely transformed to blue vanadyl sulphate.

The vanadyl-sulpha'te solution is then di.-

vided into two parts, half of which is treated at to C. with sufiicient 5 N. KOH to form a. clear coffee-brown solution of potassium vanadite to which 7 50 parts 01 Celite earth are added as a diluent, the secnolphthalein red and litmus blue. The reaction product .is sucked but not dried and constitutes a vanadyl baseexchange body.

10.2 parts of'freshlyprecipitated aluminum oxide are brought into solution with 40 parts of 100% KOH in200'parts of water. The vanadyl base exchange body described above is then stirred into the solution and a' 10%aqueous solution containing'37pparts of ferric sulphate with 18 mols of wateror' 44.4 parts of aluminum sulphate with 18 mols of water or a mixture of the-two, is added to the aluminate solution with vigorous agitation.

5 A corresponding amount of titanium sulphate, zirconium-nitrate, zinc-sulphate, thorium nitrate can also be used. 7 The reaction product is obtained, which is an aluminum base exchange body and which does not possess any catalytic properties for u the catalytic oxidation of sulphur dioxideto sulphur trioxide, is diluted with catalytically active vanadyl base exchange body and is thereby transformed into a highly active 55 catalyst for the above referred to process. i

The reaction product is sucked, pressed,

washed'with 300 to 400parts of water, dried.

"a'rid brokeninto fragments. The fragments may be treated with 5% copper sulphate, cobalt'nitrate or. iron sulphate solution to partly replace the alkali with these metals.

.This product may also be treated with salts. of. themetal. oxygen .acids of the 5th and Gth groups of the periodic system, preferably with a 1% ammonium'vanadate solution, re-

- 0nd half of the original solution added" with vigorousagitation, care being taken that the alkalinity remains between the phesultin g in a so-called salt-like bod after the soluble components have been was ed out.

The product are calcined with air or gases containing carbon dioxide at 400 (3., the calcination temperature being permitted to rise gradually in order to prevent undesirable changes in the structure of the base exchange body. After this preliminary calcination the product is then treated with 3 to 7 burner 'gases at 400 C. and is transformed into a contact mass for the contact sulphuric acid process which rocess may be carried out at temperatures 0 from 420 to 550 C.

In this example the aluminum-iron base 5 exchange-body may be considered as a complex stabilizer and stabilizer promoter for the catalyst.

In order to promote or tune the stabilizer action of the catalyst also various stabilizer promoters can be added in the. form of silivcates or heavy metal oxides such as ferric oxide, copper oxide, titanium dioxide, man ganese dioxide, zirconium dioxide, cerium dioxide, beryllium oxide, calcium oxide, 00 balt oxide or thorium dioxide. added singly or in mixtures and may advantage'ou'sly be formed in nascent state.

from 2- to 5% of such stabilizer promoters gives good results. These stabilizer promoters, of course, may be added in the same manner as any other diluent as has been generally described in several of the foregoing examples. A-diiferent method of introducing the stabilizer. promoters consists in substituting They may be I The amountof the stabilizer promoter added depends on the 'effect. desired; in general part or all of the metal salt components of the base exchanging body with corresponding amounts of 5 to 10% solutions of beryllium sulphate, silver nitrate, nickel sulphate,

or similar mineral acid salts of these bases.

Instead of embedding the catalytically active vanadylbase exchange body in the inactive base exchange body, described above,

this, or other catalytically active diluted or undiluted base exchange bodies of this class, 1

can be embedded either in the welhknown diluted or undiluted base exchanging .polysilicates or artificial neutral polysilicates.

Base exchanging aluminum iron, cadmium, titanium,\silver, copper, manganese, 2 or 3 component polysilicates are excellently suited for this purpose.- r

' Emample 12 20parts of 'a 33 B..sodium waterglass I solution are diluted with 10 volumes of water and suflicient 5% iron sulphate, copper sulphate, or silver nitrate vsoliition is added to bring about a neutral reaction to litmus. The precipitate is sucked and thoroughly washed with water to remove the alkali metal salt, and then constitutes silicates of dissolve the V 05 as potassium metavanadate. To this solution are added 40'parts of 100% KOH dissolved in 200 parts of water and 60 parts of infusorial earth or twice as much quartz or pulverized silicate rock are stirred in. The heavy metal silicate described above is then also stirred in to produce a uniform distribution.

66 parts of aluminum sulphate with 1% mols of water or an equivalent amount of beryllium sulphate, cadmium sulphate, ti-V tanium sulphate or a mixture of them are dissolved in 250' parts of water and the solution is gradually poured into suspension containing the potassium vanadate at 40 to 60 C. If necessary, 2 to 5% sulphuric acid can be added to bring the reaction to the desired alkalinity or neutrality to phenolphthalein in order to get the maximum yield.

The reaction product obtained is then pressed and washed with 300 parts of water.

A product is obtained wh1ch is an aluminum base exchange body in which the V 0 is present partly in chemically combined form and which product also contains as diluents the heavy metal silicates which may be considered as stabilizer promoters to'tune to the desired extent the composite stabilizer formed by the aluminum base ex-. change body. The contact mass is dried below 100. C. in the usual manner, broken into fragments and then calcined with air .at

together and a and 50 parts i dissolved in about 300 percentage conversion of S0 to 'tures of'about 50 to about 400 7 catalyst for the contact sulphuric acid process after it has received a preliminary treatment with gases containing 2 to 3% of S0 and excess oxygen at temperatures of about 400 to 500. The contact mass may be used with 7 to 9% burner gases at working tem-. peratures of 420 to 480 C. givin a high Q0 and displaying at the same time excellent resistance to high-temperatures,

Ewample 13 V 15 parts of V 0 are dissolved in /2 N KOH solution in the form of potassium metavanadate. 5 parts of freshly precipitated aluminum oxide are dissolved up in 35 to 40 parts of 100% KOH dissolved'in 250 parts of water forming a potassium aluminate solution. The two solutions are poured mixture of 20 parts of Tl-Og Thereupon 17 parts of aluminum sulphate with 18 mols of water mixed with 20 parts of ferric sulphate having 9 mols of Water are parts of Water and the solution is then gradually poured into the aluminate-vanadate suspension at tempera- C. v 5% sulphuric parts of V 0, are treated with suflicient 4 h N. KOH at an elevated temperature to C. and .constitutes an effective of kieselguhr are stirred in.

'mixtures, can be used.

acid is then gradually added until the desired alkalinity or neutrality to phenolphthalein is obtained. v I

The reaction product produced is a vanadium-aluminum-iron' base exchange body which contains, as a diluent, titanium oxide and kieselguhr. The productis' freed from the mother liquor in the usual manner,

washed with 3 to 4 times its weight of water and then dried ata temperature below 100 C. The product is then broken into fragments and isan excellent contact mass for the contact sulphuric acid process.

Under the usual reaction conditions, as described,in the foregoing'examples, part of the base exchange body components may be considered as stabilizers for the catalytically effective components and the titanium dioxide appears to act as a promoter for these stabilizers.

The contact mass can be also treated with water after drying in order to hydrate it and then calcined before-use. Heavy metals may alse be introduced by base exchange or salt-like bodies may be p epared.

Ewample 14 8 parts of V20 solved in 2 N. KOH containing. 26 parts of 90% KOH. 80 parts Celite brick refuse or other acid resistant materials rich in silica and 5.1 parts W0 are disare added. 22 parts'of Al (SO 18 aq.' are dissolved in about parts of water.

The suspension 1 and thesolutionQ are mixed together, adding the solution in small portions, care being taken that the reaction mixture remains strongly alkaline to litmus.

The paste obtained is freed from .the mother liquor by pressing and .is dried afterwards at temperatures under 100 C. and then broken in small pieces suitable for catalysis. I

, After drying it may be desirable sometimes to trickle water over the broken fragments in order to washout the excess of salts I formed in the preparation of this body.

The dried diluted base exchanging. containing V 0 W0 A1 0 1n non-exchangeable form is treated at 420 to 500 C.

with gases containing S02 and oxygen, first diluted and then of a concentration of 7-9% S0 The SO gas may-be obtained by burncally entrained dust.'- Y v {Instead of using Al (SO as the salt component of the base exchange body, an equivalent amount of titanium sulphate, zirconium sulphate,-chromi'um nitrate, or their body ' ,ing sulphide ores and precipitating mechani- Contact masses however which do not contain V20 usually lytic efliciency, utv their efliciency in such base exchange bodies, is greatly enhanced by the advantageous physical structure of the base exchange body.

.7 Example v 12 parts of V205 are Suspended in 250 parts'of water to form a slurry-acidified with 5 parts of concentrated sulphuric acid and then reduced to the blue vanadyl sul ture.

phate in 'the usual manner, for example, by means of gases containing S0 which are passed into the solution at boiling temperaw 107 parts of waterglass solution at 33 Be. are then diluted with 200 parts of the vanadyl silicate diluted with Celite.and'

water and about 60. parts of Celite? stirred in. The waterglass solution is then poured into the vanadyl sulphate solution; with vigorous agitation, precipitating out vanadyl silicate.

Care should be taken that after all of the solutions have reacted the resulting mixture must be made neutral to litmus if necessary with the help of small amounts of N. sulphuric acid. 10 parts of freshly precipitated aluminum hydroxide are treated with suflicient N. KOH solution to dissolve up the aluminum hydroxide in the formof potassium aluminate and to providea 10% excess of KOH. p

26.4 parts of Cr (N 0 9 aq. are dissolved in 250 to300 parts of water. The chromium may be partly or wholly replaced by equivalent amounts of titanium sulphate or aluminum sulphate. v

Into the aluminate solution is then stirred thereupon the chromium salt solution, is added producing a base exchange body in which the 'vanadyl silicate is homogeneously.

v incorporated as a diluent. Y

The reaction product is treated in the usual way by pressing and drying below 100 C. and is broken into fragments. After hydration by trickling water over the fragments the exchange. alkali art can be replaced by lead, using 5% lea nitrate solution. The alkali may also be exchanged for copper, silver, and nickel, using 5 to 10% solution, of the respective salts, the catalytic efiiciencyof such contact masses I 'being thereby enhanced. Treatment with ammonium vanadate or'molybdate, for the formation of the so-called salt-like bodies helps to increase the catalytic efiicien cy for the contact sulphuric acid process and alsothe resistance of such contact masses against high temperatures often obtained in this process.

- Ewample' Y 10 arts of A1 0 freshly precipitated are trans ormed into potassium aluminate with N. potassium hydroxide solution. 10% of do not have as high a cataalkali in excess should be present in the aluminate solution. 1

66.6 parts Al (-SO,) 3.18H2O are dissolved I in about 200 parts of water,

to partsof 'Celite brick refuse or other comminuted acid resistant materials,

such as glaucosil or neutral or base exchanging polysilicates, are stirred into the alumi: nate solution. The aluminum sulphatesolution is added in small portions with Vi orous agitation, care being taken that the 1 reaction mixture remains strongly alkaline tolitmus and preferably neutral or weakly alkaline to phenolphthalein. I

' The reaction product obtained is freed from mother liquor and dried at temperatures below C. The material thus obtained is broken in small fra ments and consists of a catalytically ine ective base 'ex-' changing'body diluted with inactive materials.

' The fragments are hydrated by trickling ly with soluble vanadate solutions such as ammonium vanadate and potassium 'vana date, in order to form the vanadate of the dilutedbase exchange body containing silver in exchangeable form.

After again drying the particles which now possess a perfectly uniform yellow color are calcinated first with air and then at 400 to 450'? (3., with SO gases strongly diluted with air. v

6 to 9% burner gases, freed from dust, but containing the so-called catalyst poisons are passed over this contact mass at 450 to 550 (land in a short time a good contact sulphuric. acid process starts, giving high percentage conversions at; regular gas velocities, that is to say, when 200 volumes of the said contact mass are treated with 1300 to 1500 volumes of burner gases.

The aluminate component can be replaced wholly or partly byother amphoteric metallates such as those containing Zn, Be, Cd, Pb, singly or in admixture.

The aluminum sulphate component as the salt component of the base exchanging body can also wholly or partly be replaced by salt solutions such as the salts of Fe, Cr, N Co, Mn, Cu, Be, Zr, T'h, Ti, Ag, Cd, Sn,-Ue,

Pb, alone or in admixture.

. Example 17 00 parts of33 B. sodium waterglass so-' lution are diluted with 15 to 20 volumes of.

water and 60 to' 80 parts of infusorial earth" added. Sufficient 5% iron sulphate, copper sulphate, SilVBl nitrate, calcium chloride,

strontium chloride, and manganese nitrate neutral silicates of the metals used which.

solution, sirgy or in admixture are added. with vigorous agitation to bring about a neutral reaction to litmus.

' The precipitate is sucked and thoroughly washed withv water to get the alkali metal saltout of it and then constitutes diluted kneaded with the aluminate mixture'and affor addition of all the solution, an alkaline or neutral reaction to phenolphthalein'shonld be obtained.

The diluted reaction product so obtained is freed from mother liquor by pressing, dried at temperatures under 100 C. and

broken in pieces. The dried fragments are leached ml by trickling water over them and then are r ai'ed wlth vanadyl sul- "phate solution. chromium nitrate solution or uranyl nitrate solution or a mixture'of them,

alkali for those radicals; -Thereupon impregnate the products with a dilutedpotassiuni or ammonium vanadate solution in order to form the so-called salt-like body that is, the vanadate of the vanadyl base exchange body diluted .with silicates and infusorial earth. r

' After drying and calcining, the contact mass thus obtained is treated with 6 to 9% burner gases at 430 to 550 (l'developing 1 a good working contact sulphuric acid process wherein the contact mass shows a good resistance against high temperatures obtaining in the process and against the usual gas-. eous catalytic poisons. I

The silicates in this contactmas's act-as stabilizer promoters in the reaction.

The metallate component, as well as the" metal salt component, can be wholly or partly replaced by corresponding elements as described in Example 16.

Instead of using neutral silicates as stabilizer promoters 5 to 10% of TiO Fe O based on the amount of diluent used, can be ther oughly admixed.

The base exchange bodies, as described in Examples 16 and 17 can'alSo be prepared by the other methods as described in the specification.

Example 18 1'. A mixture of-10 parts of V 05 and 4 parts of W )1. are dissolved in 300 parts of diluted KOl-l solution containing 10.5 parts of 90 )b KOH. To this solution under vigor- 2. 6 parts of 150 to 200 parts of water and sufficient conous agitation about 90 parts fC elite brick refuse or a mixture of comminuted quartz and diatomaceous earth equal in volume to Celite brick refuse are added.

- The suspension is heatedup to 8090 C.

and is gradually made faintly acid to congo using 2 N. sulphuric acid in orderto precipitate out in the diluted V 0 and W0 The mixture obtained is then dried.

2. 22 parts ofAlflSO.) l8 aq. are transformed in-the usual way, by means of am monia, memoir). and the wet A1 3011)., is dissolved in 14 parts of 90% .KOH with about parts of water in order to form the corresponding aluminate.

The dried V 0 and WO is impregnated with the 'aluminate solution; by kneading thoroughly and then formed in suitable iluted v pieces. These formed pieces'are then dried I at temperatures under 100 C. with CO containing gases whereby a diluted base exchange body is obtained containing V 0 W0 and A1 0 in non-exchangeable form.

The contact mass so obtained is calcined with S05 gases greatly diluted by air and when treated with 7-9% burner gases a very efficient contact sulphuric acid process develops.

Instead of V 0 and W0 other catalytically effective components can be used in this contact mass such as V 0 M00 Instead of using a potassium aluminate solution other metallates of amphoteric elements can be used'such as Cd, Cr. and Be. Inorder to increase the resistance of such contact masses to high temperatures often obtaining in the contact sulphuric acid process so-called stabilizer promoters for example 5% Fe O C110,. TiO can be embedded during the formation of the-contact. mass.

Example 19 1. 12 parts of V 0 are dissolved in 150 to 200 parts of water containing 10 parts of %KOH.

CuSO; 5 aq. are dissolved in centrated ammonia solution is added until a clear blue solution of the cuprammonium sulphate is obtained.

3. 5 parts of freshly precipitated A1 0 are dissolved in the corresponding amount of 2 'N. KOH solution in order to form the potassium aluminate.

refuse are added in order to form a suspenj sion of this diluent in themixedsolutions.

Solution f#1'is poured in'withvigorous agitation and. then a thin stream of 2 N. H 50 is addediuntil the 'reactionjmixture is slight- The product so obtained is freed from the mother liquor 1 by filterin and pressing. The press-cake is then drie at temperatures l'y alkaline or-neutral to phenolphthalein.f

acid process'sets in.

preferabl below 100- C. and then broken in small ragments. v

Before use this contact mass is calcined with air at 400 C. in order to' dehydrate the mass.

2 to 4'volumes of the contact mass thus produced are filled in a sulphuric acid converter and 1000 to 2000 volumes of 7 to 9% burner gases are passed over the mass per hour at a temperature about 440 to 520 C. whereupon a very eflicient .contact sulphuric Example Pea sized .quartz fragments are treated with a 20% solution of hydrofluoric acid in order to. etch the surface of the quartz fragments. On these carrier fragments is formed a base exchange .body containing platinum, the. amount of coating being about 10% to volume of the carrier fragments.

Instead of forming the base exchange body. in situ on the fragments, the finished base exchange body may be pulverized and after-. wardscoated on the carrier fragments with v, the help of adhesive substances such as 1v vlpterglassMgSO .KOH, NaOH, and the The base exchange the following way:

body is prepared in tassium aluminate using a 5 N. potassium hydroxide solution and after the formation of the potassium aluminate an excess of alkali amounting to 1015% should be present. 4 parts of H PtCI as a 10% solution are then added to the aluminate solution with vigorous agitation. 22 parts of Fe2( 9 are dissolved in 200 parts of water 'and are then added gradually with vigorous agitation, care being taken that the resulting reaction product remains slightly alkaline or neutral to phenolphthalein.

The base exchange body obtained and containing aluminum, iron and platinum in non-exchangeable form is freed from the mother liquor by pi'essin and dried at tem peratures of about 100 Instead of an undiluted base exchange body a diluted base exchange body can be used, especially when using powdered quartz or material rich in silica such'as colloidal SiO kieselguhr and the like, and it is-an effective catalyst for the contact sulphuric acid process and can also be coated on tocarrier ragments as described above whereby a large sa'vingof platinum is obtained.

Example 21 6.7 parts of freshly precipitated A1 0 are mixed with 12 parts V 0 and suificient crys-.

'tallized oxalic acid or other reducing agents,

such as owdered carbon, are added to reduce u the V, in the reaction mixture to V t) 5 parts of A1 0 aretransformed into po-- Thereupon 11 parts of 100% KOH or 13 parts of K 00 are thoroughly mixed with the others. The entire mixture is then heated up to the'sintering point or to incipient melting. I

The melted mass is crushed to small pieces and leached out with water in order to remove excessive alkali. The catalytically active base exchange body thus obtained is ground and then embedded in a catalytically inactive zeolite body asfollows:

90 parts of 33 B. waterglass are exchange body obtained as described .above together with SOpartsof infusorial earth are added with vigorous stirring in order to obtain a good distribution. parts of alu-' minum sulphate with 18 mols of water are dissolved in 200 parts of water and suflicient 10 N. potassium hydroxide solution is added to dissolve up the aluminum oxide which is at first precipitated forming a potassium aluminate "solution; The alumiuate solution is then stirred into this suspension and the mixture heated up to about '60 to C. A gelatinous precipitate is obtained almost at once and is increased by the gradual addition of 2 N. sulphuric acid. Care should be taken, however, that alkalinity to litmus or neutrality to phenolphthalein is maintained. The stirring is continued for an diluted with 5 to 10 volumes of water and the base hour during which period the mixtureis v gradually permitted to cool down to room temperature. The gelatinous precipitateobtained is pressed and washed w th 200 parts of water in small portions. The filter cake 'is then dried at about'80--C. and broken .Emample 22 1 60 to 80 parts of Celite brick refuse are impregnated with an ammoniacal silver vanadate solution prepared by causing 18 parts of V 0 in the form'of sodium metavanadate dissolved in 250 parts of water to react with 34 parts of silver nitrate also dissolved in about 250 parts of water.

The yellow silver vanadate which is precipitated is then separated from the mother liquor in the usual manner and suspended in about parts of water in the form of a slurry. 20 per cent ammonia water is added until all of the silver vanadate, dissolves. After the impregnation of the Celite brick refuse with this solution, the impregnated material is warmed to completely drive ofi the ammonia. i 7.75 parts of W0 are dissolved with N. KOH solution of potassium tuligstate.

tilt

product reacts alkaline or neutral to phenolphthalein. The reaction mixture is freed from the mother liquor by suction and is washed with about 200 parts of water and thendried at temperatures preferably below 100.C.. The dried precipitate is broken into small fragments suitable for the contact sul phuric acid process and then carefully cal cined with air at about 400 0.: 1 r

The calcined contact mass after pretreating with diluted burner gases for a short while develops, with 6 to 9% burner gases,

an eflicient contact sulphuric acid process-at 420 to 550 C. using the well known gas velocities. I

This contact mass consists of a base exchange body containingtungsten and aluminum in non-exchangeable form which combination has catalytic efliciency in the contact sulphuric acid process; The diluent embedded in this catalytic active base exchangebody is a further catalytically active component in the process and the combination of both creates anefiicient contact mass.

Instead of embedding silver vanadate other vanadates can be used especially the vanadates of the heavy metals, such as, copper, iron, cobaltand the like.

Also, for the preparation of the base exchange body other catalytically active components. such as, V 0 V 0 M00 and instead of aluminum, also other amphoteric' metal oxides, can be applied-whereby effective catalysts will be obtained.

Example 23 6 parts of V 0 are suspended in 150 parts of water to form a slurry acidified with 5 parts of concentrated sulphuric acid and then reduced to the blue vanadyl sulphate in the usual manner. For example, by means of gases containing S0 which are-passed into the solution at, the boiling temperature. 54 parts of a waterglass solution of 33 B. are diluted with -100 parts of water and about parts of Celite brick refuse are stirred in. The waterglass solutionis then poured into the vanadyl sulphate solution. with vigorous agitation, precipitating out= vanadylsilicate. Care should be taken that after all the solutions have reacted, the resulting' mixture must be made neutral to litmus, if necessary with the help of small amountsof N. sulphuric acid. a 1 10 parts of freshly precipitated aluminum oxide are treated with suflicient N. KQH

solution to dissolve up the aluminum oxide in the form of potassiumaluminate and to provide a 510%. excess of 'KOH.

, 6 parts of V 0 are transformed, as described above, to vanadyl sulphate and dis: solved in about 250 to 300 parts of water.

The vanadyl silicate obtained above is stirred into the vanadyl sulphate solution and under vigorousagitation the potassium aluminate is added and a base exchan" e body is obtained containing V 0 and A1 3 in non-exchangeable form diluted with vanadyl silicate and Celite brick refuse.

In adding. the potassium .aluminate, care should be taken that the reaction mixture must react at least neutral or alkaline to phenolphthalein, small amounts of addi tional alkali being used if necessary.

The reaction mixture is separated from themother liquor in the usual way and then 79% burner gases whereupon a very eflicient contact sulphuric acid process sets in attemperatures between 420 and 550 C. i

'It'will be noted that in Example 23, the metallate [solution is added to the metal salt solution instead of vice versain the other examples. I find that for most contact masses it. is desirable to add. the metal salt solution to the metallate solution in order -to assure a suitable alkalinity of reaction mixture thruout the whole reaction. Some very effective contact masses such as that described in Example 23 may be produced by the converse method of adding the metal- I late to the metal salt solution and processes using such contact masses are included in the present invention.

In the claims and specification the term base exchange body isstrictly limited toproducts which are analogous to the zeolites -but do not contain silicon and are capable of reversibly exchanging bases with salt solutions. The expression does notcover ordinary salts which are capable of undergoing metathesis in which their basic'ra'dical change their bases after v the nature of,

zeolites.

- In the claims the expression calcination is used to cover the treatment of the fresh contact mass with hot gases, preferably hot SOL; gases. This calcination is in effect a contact sulfuric acid process, carried out usually with diluted S0 gases. The term cal prises passing a gaseous mixture containing sulphur dioxlde and oxygen at an elevated temperature over-a catalyst which prior tocalcination contains at least one catalytically active non-silicious base exchange body.

2. A process of catalytically oxidizing sulphurdioxide to sulphur trioxide, which comprises passing a "gaseous mixture containing sulphur dioxide and oxygen at an elevated temperature over a catalyst which prior to calcinationcontains at least one non-silicious base exchange body, containing at least one eatalytically active component chemically combined in non-exchangeable form. 3. A process of catalytlcally oxidizing sulphur dioxide to sulphur trioxide, which comprises passin agaseous mixture containing sulphur dioxide and oxygen at an elevated tem ,erature over a catalyst which prior to calclna-tion contains at least one catalytically active non-silicious base exchange body which contains no-elements of the platinum group.

4. A process according to claim 3, in which the reaction gases are freed from mechanlcall entrained dust before passing over the.

- cata yst, but which contain poisons for platprises passing a gaseous mixture containing cal homogeneous structure.

sulphur dioxide and oxygen at an elevated tem erature over a catalyst which prior to- .calc'ina-tion contains at least one catalytically active non-silicious base exchange body con- I. ta'imng vanadium in non-exchangeable form.

' 6' v A -process of catalytically oxidizing sulphur dioxide to sulphur trioxide, which comprises' passing a gaseous mixture containingsulphur dioxlde and oxygen at an elevated temperature over acontact mass which prior to calcination' contains at least one catalyti callyactive non-silicious base exchange body admixed withv diluent bodies to form a physi- -7. A process of catalytically oxidizing'sulphur dioxide to sulphur trioxlde, which c0mprises passing a. gaseous mixture containin sulphur dioxide and'oxygen. at an elevate v to temperature over acontact mass which rior to calcination contains at least one cata ytically active non-silicious base exchange body coated onto massive carrierfra ents. e 4 8. Aprocess,'ac cording to claim 6, in which the" diluents contain stabilizer romoters.

9. A process, according to claim 6, in'wliich I the diluents contain catalytically inefiecti've base exchange bodies. I 1

, 10. ,Af-proc'ess according to claim 6, inwhichf the diluents contain zeolites. v

I 11. A process of catalytically oxidizing sulphur dioxide to sulphur trioxide, which comprises passing a gaseous mixture containing sulphur dioxide and oxygen at an elevated temperature over a catalyst which prior to calcination contains at least'one'non-silicious. base exchange body which has been caused to react with at least one catalytically efi'ective acid radical to form therewith a salt-like body. Y r I a 12. A process of catalytically oxidizing sulphur dioxide to sulphur trioxide, which comprises passing a gaseous mixture containing sulphur dioxide and oxygen "at an elevated temperature over a catalyst. which prior to calcination contains at least one non-silicious base exchange body which has been caused'to react with a vanadium-containing acid radical to form a salt-like-body.

13. A process, according to, claim 11, in

which the non-silicious base exchange body is catalytically ineffective.

14. A process, according at least one compound of vanadium other than a compound containing vanadium and to claim 12, in which the non-silicious base exchange body is silicon having an activity not less than standard platinum catalysts and being resistant to temperatures of the reaction for long periods of time, said compound of vanadium being :a polyvanadate.

16. A process of catalytically oxidizing P sulphur dioxide to sulphur trioxide, which comprises passing a gaseous mixture containing sulphur'dioxide and oxygen at elevated temperatures over a contact mass which after commencement of the reaction contains at least one compound of vanadium other than a compound contamlng vanadlum' and silicon having an activity not less than I standard platinum catalysts and beingresistant to temperatures of the reaction for long periods of time, said compound of vanadium being a complex compound containing aluminum and vanadium.

17. A sulphur ioxide to sulphur trioxide, which comprises passing agaseous mixture containingsulphur dioxide andoxygen at elevated temperatures over a contact mass (which after commencement of the reaction contains atleast one compound of vanadium other than a .compound containing vanadiuin and silicon having an activity not less vanadiumbeing a polyvanadate and being rocess of catalytically oxidizing A ph sically associated with non-catalytically active diluent bodies. i 1 '18. A process of catalytically oxidizing sulphur dioxide to sulphur trioxide, which comprises Passing 'a gaseous mixture containing sulphur dioxide and oxygen at ele; vated temperatures over a contact mass which after commencement of the "reaction contains at least one compound, of vanadium other than a compound containing vanadium and silicon having an activity not less than standard platinum. catalysts and comprises passing a gaseous mixture con-- taining sulphur dioxide and-oxygen atcelevated temperatures over a contact mass which after-commencement of the reaction contains at least one compound ofvanadium other than a compound containing vanadium and silicon-having an activity not less than standard platinum catalysts and being resistant to tem eratures-of the reaction: for long periods 0 time, said compound of vanadium being a complex compound other than a polysilicate and being associated with carriers at least a part of which are diluted, catalytically ineffective base exchange bodies, I a

20. A process of catalytically oxidizing sulphur dioxide to sulphur'trioxide, which comprises passing a gaseous mixture containing sulphur dioxide and oxygen at elevated temperatures over a contact mass which after commencement of the reaction contains at least one compound of vanadium other than a compound containing Vanadium and silicon having an activity not less than standard platinum catalysts and being resistant to temperatures of the reaction for long periods of time, said compound of vanadium being a complex compound in which a vanadium radical constitutes at least a part of the acidic portion of the compound and in which the compound is associated with carriers at least a part of which arediluted, catalytically ineffective base exchange bodies.

21. A process of catalytically oxidizing sulphur dioxide to sulphur trioxide, which comprises passing a gaseous. mixture containing sulphur dioxide andoxygen at elevated temperatures over a contact mass which after commencement of the reaction contains at least one compound of vanadium other than of time, said compound of vanadiumbeing a polyvanadate 'andbeing associated with carriers at leasta part of which are diluted, catalytically inefiective base exchange bodies.

22. A process of catalytically oxidizing sulphur dioxide to sulphur trioxide, which comprises passing a gaseous mixture containing sulphur dioxide and oxygen at elevated temperatures over a contact mass which after commencement. of the reaction contains at least one compound of vanadium other than a compound containing vanadium and silicon having an activity not less than standard platinum catalysts and being resistant to temperatures of the reaction for long periods of time, sa1d compound of vanadium being a complex compound contammgalummum and being associated with carriers at least a part of which are diluted, catalytically ineffective base exchange bodies.

23.-A recess of catalytically oxidizing sulphur ioxide to sulphur trioxide, which comprises passing a gaseous mixture containmg sulphur dioxide and oxygen at elevated temperatures over a contact mass which after commencement of the reaction contains at least one compound of vanadium other than a compound containing vanadium and sili- 0011', which compound is microporous, said compound of vanadium being a polyvanadate.

' 24.'A process of catalytically oxidizing sulphur dioxide to sulphur trioxide, which comprises passing a gaseous mixture containing sulphur dioxide and oxygen at clevated contains at least one compound of vanadium other than acompound containing vanadium and silicon, which compound is nncroporous,

said compound of vanadium containing vanadium and aluminum.

26. A process of catalytically oxidizing sulphur dioxideto sulphur trioxide, which comprises passing a gaseous mixture containing sulphur dioxide and oxygen at elevated temperatures over a contact mass which after connncm'cment oi the reaction contains at least one compound of vanadium other than a'couipound containing vanadium and silicon, which compound has a porosity not less fine than that of non-silicious base ex-.

I change bodies, said compound of vanadium containing vanadium and aluminum.

27 A'process of catalytically oxidizing sulphur dioxide to sulphur trioxide, which comprises passing a gaseous mixture containing sulphur dioxide and oxygen at ole f vated temperatures over a contact mass which after commencement of the reaction contains at least one compound of vanadium containing polyacid.

other than a compound containing vanadium and silicon, which compoundis microporous, and contalns an aluminum salt of a vanadium 28. A process of sulphur dioxide to sulphur trioxide, which comprises passing a gaseous mixture con-tain- 1 ing sulphur dioxide and oxygen at'elevated temperatures over a contact mass which after commencement of the reaction contains at least one compound of vanadium other than a compoundcontaining vanadium and sili-' con, which compound has a porosity not less fine than that of non silicious base exchange bodies, and contains an aluminum salt of a vanadium containing pol acid.

29. A process of cata ytically oxidizing v sulphur-dioxide to a sulphur trioxide, which comprises passing a gaseous mixture con-- taming sulphur dioxide and oxygen at elevated temperaturesover a contact mass which 1 after commencement of the reaction contains at least one compound of vanadlum other than a compound containing vanadium and silicon having an activity not less than standard platinum catalysts and being resistant to temperatures of the reaction for long periods of-time, said compound of vanadium containing aluminum.

.30. A process of catalytically oxidizing sulphurdioxide to sulphur trioxide, which comprises passing a gaseous mixture contain- I con having an activity notless than standing sulphur dioxide and oxygen at elevated temperatures over a contact mass which after commencement of the reaction contains at least one compound of vanadium other than a compound containing vanadium and siliard platinum catalysts andbeing resistant to temperatures of the reaction for longperiods of time,- said compound of vanadium containing aluminum and being physically associated with'non-catalytically 'active diluent bodies.

31. A process of ,catalyticallyoxidizing.'

sulphur dioxide to sulphur trioxide, which comprises passinga gaseous mixture containing sulphur dioxide and oxygen at elevated temperatures over a contact'mass which after commencement of the reaction contains at. least one compound of vanadium other than: 1 a compound containingvanadium and sili- I con having an activity not less than standard platinuln'catalystsand being resistant to temperatures of the reaction for long periods of. time, saidcompound of vanadmm concatalytically oxidizing taining aluminum andbeing associated with carriers at least a part of which are diluted,

catalytically ineffective base exchange bodies;

Signed at Pittsburgh, Pennsylvania,.this

2nd ay ofApril 1930'.

I ALPHONS O. JAEGER. 

